Rolling mill with set elongation



Aug. 22, 1950 P. BLAIN 2,519,818

ROLLING mm. WITH sm ELQNGATION Fig. 2

Aug. 22, 1950 P. BLAIN 2,519,818

Romuc MILL wrm SET ELONGATION Filed Aug. 9, 1946 2 Sheets-Sheet 2mvfNfoR PAUL 54AM ATTORNEY Patented Aug. 22, 1950 ROLLING MILL WITH SETELONGATION Paul Blain, Paris, France, minor to Soclete Anonyme desAcieries et Forges do Firminy, Paris, France, a body corporate France 1Application August 9, 1946, Serial No. 889,359

In France February 23, 1948 1 Claim. (01. 80--58) A rolling mill with aset elongation is a mill that allows the reduction in thickness of aband in a given ratio, consequently a stretching of the band in the sameratio whatever may be the thickness oi the band as it enters the rolls.

In accordance with a known form of execution of such a mill, drawing setin which the band travels are located respectively fore and aft 0! themill stand; each set contains a certain number of rollers that areinterconnected by gearing arranged so that the peripheral speed of allthe rollers of one set is the same; in addition, the two drawing setsare interconnected by a mechanical drive ensuring a fixed ratio betweentheir respective speeds.

The rolled band, that unrolls from a first winding drum, travels in theforce drawing appliance, into the mill, then into the aft drawingappliance to roll up finally on the second winding drum; it cannot slipon the rollers of the first drawing set or on those of the second set,so there is necessarily an elongation in the mill in the ratio thatthere is between the peripheral speeds of the rollers of the first setand that of the second set and this is so whatever may be the thickness01 the band going into the rolling mill.

My invention has for its object a mill with set elongation in which theclosure of the rolls is regulated at each instant by the action of acontrivance for measuring the ratio of the speeds of the band as itenters and as it leaves the rolls.

To do this, the band can travel fore and aft of the rollstand on drivingrollers that transmit their movement to a contrivance that controls theadjusting or the slackening of the mill depending on whether therelative speed of the rollers is below or above a fixed ratio.

The attached drawing shows as an example a form of execution of myinvention.

Figs. 1 and 2 show diagrammatically the mill respectively in elevationand in plan view.

Figs. 3 and 4 show similar side and front views of the regulatingcontrivance.

The stand I of the rolling mill is furnished with a hydraulicadjustingjack 2; the band unrolls from the drum 3 to wind on to the drum 4; afterrolling, the drums are driven respectively by motors 5 and 6, in such away that the band is under tensile strain as it enters and as it leavesthe rolls; the driving rollers I and 8 are drawn by the hand. Theserollers transmit their movement through gears a and ill to a contrivanceIi that closes a contact when the ratio of the peripheral speeds of therollers l and 8 falls below 2 a given figure and opens this contact whenthe ratio exceeds this figure. This contact is placed in a circuitcomprising an electromotive force and an electro-magnet that controls ahydraulic relay putting the adjusting jacks in communication withhigh-pressure mains if the ratio oi. the speeds of the rollers is toolow and with the exhaust if this ratio is too high. In such conditions,the rolling pressure is fixed at an average 10 figure such that theband, whatever its thickness as it enters the rolls, undergoes in itstravel through the mill the exact elongation for which the contrivanceII is regulated.

For this purpose, the disc Ii is controlled by the roller on the insideI and the parallel disc I2 is controlled by the roller on the outside 8(Figs. 3 and 4). These two discs are placed opposite to each other withtheir planes parallel but with their axes l8 and H set back. A smallwheel it turns round an axis i8 hinged at II to a point midway on theline of the centres of the axes i3 and I l, and bears on the two platesthat turn in opposite directions. In these conditions, the axis It takesa position that depends only on the figure of the ratio of the speeds ofthe discs II and l2, 1. e. of the ratio of the speeds of the rollers atthe entry and exit from the rolls if the drives between rollers anddiscs are the same on the in and "out sides; a ferrule 18 insulated withreference to ground fixed on the axis [6 cooperates with contact I9 soplaced that its position can be regulated in line with the elongationthat is desired during the travel through the rolls. A circuit connectsa suitable E. M. F. 20, the contact i8'l9 andan electromagnet 2! thatcan attract a blade 22 attached to the ram 23 of a hydraulic distributor24. In the position shown, taking the contact l8i9 as 0 open, the ramand the blade of the hydraulic distributor are, in their lower position,urged by the spring 25. Under these conditions, communication is made bythe distributor between the adjusting Jacks z and the exhaust 21. Whencontact is established at 58-49, the blade is attracted and thehydraulic distributor 24 links up the adjusting jacks 26 with an inletof highpressure water 28. The hydraulic distributor thus putsalternatively the jacks in communication with the exhaust or with thehigh-pressure mains as the elongation that the band undergoes in therolling mill exceeds the predetermined ratio or falls below this figure.On an average, the elongation of the band has then this predeterminedfigure and the fluctuations above and be- 3 low this elongation can bereduced to a very low amount. Instead of direct action of the hydraulicdistributor on the feed of high-pressure water to the jacks, these jackscan be connected on the high pressure side of a hydraulic multiplicatorwhile the distributor delivers water at a lower pressure to the lowpressure side of the multiplicator.

It is also possible to design a form of execution of my improved rollingmill with set elongation in which the mill is furnished with amechanical adjusting device with screws or wedges, with the adjustingregulated automatically in line with the readings supplied by thecontrlvance ii that measures at each moment the elongation that the bandundergoes in the rolling mill.

Obviously, the form of execution that has been described above withreference to the attached drawings has been offered purely as a guideand by no means as a limitation, and my invention allows the applicationof any device that provides for the adjustment of the adjusting of therolling mill stand in line with the ratio of the 25 4 a set of rolls forchanging the cross-section of a strip of material, means for adjustingsaid rolls, strip driven means at the inlet side and strip driven meansat the outlet side of said set of rolls, two parallel discs rotatableabout'parallel axes offset in relation to each other, a rod rockingabout an axis located midway between the axes of said discs, a rollerloosely mounted on said rod and frictionally driven against the two saiddiscs, means to cause said discs to rotate in opposite directions atspeeds which are respectively proportional to the speeds of said stripdriven means at the inlet and outlet sides of said set of rolls, anelectric switch controlled by the rockings of said rod and means forcausin said switch to control said adjusting means.

PAUL BLAIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,968,790 Steckel et a1. July 31,1934 2,051,018 Umansky Aug. 11, 1936 2,194,078 Simonds Mar. 19, 1940

